In the Middle ages it was a "fact" that there were four colors in a rainbow, and four elements.
That's not a fact, though I recognize you put quotes around the word. That was an opinion about the facts that turned out to be wrong.
Today the physicist Brian Cox writes "whatever can happen, does happen at the quantum level".
That's not a fact either. That's an interpretation of quantum mechanics, an attempt to translate its concepts from the language of math into plain English. Attempts like these never really work, and this one is no exception.
Facts are statements about our expectancies and our limited ability to control what we call "the world".
Says who? Certainly common usage in American English implies no such thing. (See my response to JLNobody
.) You, too, seem to speak some private language of your own, while letting your correspondents believe you're speaking English.
What we call the world changes as we change.
Exactly. Our words for the world and the things in it change; the world itself does not.
The word "gravity" implies we know how to predict the movement of what we call "bodies" in what we call "a gravitational field". But do we call that parochial knowledge the fact or do we eliminate the term "gravity" entirely and use Einstein's "space tells matter how to move, matter tells space how to curve" as the fact ?
There is a broad domain of physical phenomena where the predictions of Newtonian physics are consistent with observation. Our entire everyday lives are included in this domain. Within it, there is no difference between Newtonian and Einsteinian physics, so we may as well keep our Newtonian terminology.
There are other domains where the general theory of relativity makes predictions consistent with evidence and Newtonian physics do not. (Gravitational lenses and such.) In these domains, Newtonian physics is wrong --- and has always been.